1. Field of the Invention
This invention relates generally to devices which are designed to prevent loss of shopping carts from shopping centers and the like. More particularly, it relates to a specific wheel design which has a braking mechanism activated by deviation of the longitudinal axis of the shopping cart from the horizontal.
2. Prior Art
Many devices have been disclosed in the prior art which basically fall into two general classes. First, there are those devices typified by U.S. Pat. No. 3,356,185 by Isaack which involve braking devices which engage the wheels of a shopping cart in some manner which prevents rotation thereby braking the cart. Second there are those devices as typified by U.S. Pat. No. 3,405,783 to Clark which cause entrapment of the wheels of said cart such that either the hub of the wheels or some other portion of the cart engages the surface of the entraping mechanism. The instant invention falls generally into the first category. As can be noted, however, the device in Isaack is very complex and does not cause braking until the wheel is raised off the ground, hence one could simply exit down a driveway with such a cart and thereby defeat the purpose of the mechanism. Alternatively, very expensive groving of driveways and other areas is required to entrap or otherwise engage wheels of carts which creates a dangerous surface condition and increases the likelihood of a customer or other person tripping or falling because of the surface deviation necessary for the device to operate. The instant invention utilized the existing surface conditions with little, if any, modification to provide the braking action. The instant invention addresses these inherent prior art defects as is described herein and accordingly, it is an object of this invention to provide a braking apparatus which allows a very simple maintenance free wheel locking construction. It is a further object of this invention to provide a braking apparatus which will engage and disengage automatically.